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Ptolemy

Κλαυδίου Πτολεμαίου μαθηματικῆς τετραβίβλου συντάξεως

ΒΙΒΛÍΟΝ Α΄.

‹ᾱ. Προοίμιον›

Cam.2 p. 1Τῶν τὸ δι᾿ ἀστρονομίας προγνωστικὸν τέλος παρασκευαζόντων,1 ὦ Σύρε, δύο τῶν μεγίστων καὶ κυριωτάτων ὑπαρχόντων, ἑνὸς μὲν τοῦ πρώτου καὶ τάξει καὶ δυνάμει, καθ᾿ ὃ τοὺς γινομένους ἑκάστοτε σχηματισμοὺς τῶν κινήσεων ἡλίου καὶ σελήνης καὶ ἀστέρων2 πρὸς ἀλλήλους τε καὶ τὴν γῆν καταλαμβανόμεθα· δευτέρου δὲ καθ᾿ ὃ διὰ τῆς φυσικῆς τῶν σχηματισμῶν αὐτῶν ἰδιοτροπίας τὰς ἀποτελουμένας μεταβολὰς τῶν ἐμπεριεχομένων ἐπισκεπτόμεθα· τὸ μὲν πρῶτον ἰδίαν ἔχον καὶ δι᾿ ἑαυτὴν αἱρετὴν θεωρίαν, κἂν μὴ τὸ ἐκ τῆς ἐπιζεύξεως τοῦ δευτέρου τέλος συμπεραίνηται, κατ᾿ ἰδίαν σύνταξιν ὡς μάλιστα ἐνῆν ἀποδεικτικῶς σοι3 περιώδευται. περὶ δὲ τοῦ δευτέρου καὶ μὴ ὡσαύτως αὐτοτέλους ἡμεῖς ἐν τῷ παρόντι ποιησόμεθα λόγον κατὰ τὸν ἁρμόζοντα φιλοσοφίᾳ τρόπον καὶ ὡς ἄν τις φιλαλήθει μάλιστα χρώμενος σκοπῷ μήτε τὴν κατάληψιν αὐτοῦ παραβάλλοι τῇ τοῦ πρώτου καὶ ἀεὶ ὡσαύτως ἔχοντος βεβαιότητι, τὸ ἐν πολλοῖς ἀσθενὲς

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Tetrabiblos I.

The Quadripartite Mathematical Treatise, or “Tetrabiblos,” of Claudius Ptolemy.

Book I.

1. Introduction.

Of the means of prediction through astronomy, O Syrus, two are the most important and valid. One, which is first1 both in order and in effectiveness, is that whereby we apprehend the aspects of the movements of sun, moon, and stars in relation to each other and to the earth, as they occur from time to time; the second is that in which by means of the natural character of these aspects themselves we investigate the changes which they bring about in that which they surround. The first of these, which has its own science, desirable in itself even though it does not attain the result given by its combination with the second, has been expounded to you as best we could in its own treatise2 by the method of demonstration. We shall now give an account of the second and less self-sufficient method in a properly philosophical way, so that one whose aim is the truth might never compare its perceptions with the sureness of the first, unvarying science, for he ascribes to it the weakness and unpredictability

  • 1Astronomy proper.
  • 2The Almagest.
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DOI: 10.4159/DLCL.ptolemy-tetrabiblos.1940